Lehmannaudio Decade Phono Stage Review

[KSTR]

Weird to see such a beefy power supply, and real heat sinks for output devices, and yet have headroom be the limiting factor.

It is a passive design with most of the gain happening (in the THAT1510) before the RIAA equalizer circuit and some final gain at the output, compromising headroom (the higher the frequency the lower the headroom as the passive EQ can only reduce levels vs frequency).
The graphs indicate and the manufacturer's info on their website confirms this.
EDIT: crossposting with @LTig

 

[KSTR]

But no XLR
I kow Cinch is used with most home devices but as the signal has to travel via the shield it is always prone to mains hum. If a computer is somewhere in the chain you also may get noise from its power supply especially if it is external and grounded.
So I personally dislike Cinch a lot. All the interconnections in my system are XLR
Would be interesting to know which Phono Pre offers XLR…

Please understand that for a balanced connection you only need a balanced input, not a balanced output.
Place an RCA to XLR adapter at the source end, done.

 

[gvl]

At this price and performance they should include a companion vacuum vinyl cleaner for free. Perhaps this is what the second PSU connector is for?

 

[amirm]

One thing to add, @amirm , when you test frequency response do you drive both channels (mono)? If not, you may not get the correct (relevant) response when the phono stage implements a differential high-pass filter.

Below sim is for a simple 1st order differential highpass together with the common-mode highpass.
Green is for mono which is the relevant case for us (as low bass is effectively mono on vinyl), blue is for one channel driven only, and red is for out-of-phase signals (rumble attenuation).
View attachment 351513

I drive both channels but for clarity only show one.

 

[amirm]

@amirm: could you run a dashboard with MC in high gain mode? Somehow I feel this is missing ...

I shipped the unit already as it been here fir 5 months!

 

[LTig]

I shipped the unit already as it been here fir 5 months!

Nevermind - there are enough flaws to not buy it anyway.

 

[Endibol]

That's wrong.
The latin prefixes sub- and infra- mean the same thing and can be interchanged. Same with ultra- and super-.
When used with an adjective like -sonic you also need a subject to which is it applied, which in our case it is frequency.
The subject is often omitted when it is clear from the context, similar to frequency response which needs a subject, the frequency response of which quantity. Sound pressure level, mostly.

You are referring to speed of sound, though.

English tends to be a somewhat sloppy language when it comes to properly describe things, compared to German at least.

@KSTR Sorry, you are wrong, peniku8 is right. Here frequencies below a certain range of sound are meant, so infrasonic is the correct expression. “Sub” would be used to directly compare one specific frequency range to another, for instance: “ This filter blocks sub-treble frequencies”. The differences between “sub” and “ultra” are subtle though..

 

[JSmith]

Just to clarify, subsonic and infrasonic whilst similar in definition are quite different;

Subsonic refers to sounds that have a frequency below the audible range of the human ear, which is typically 20 Hz to 20,000 Hz. Infrasonic, on the other hand, refers to sounds that have a frequency below 20 Hz, which is also below the range of human hearing.

Subsonic frequencies refer to sound waves that have a frequency below the range of human hearing, while infrasonic frequencies refer to sound waves that have a frequency below 20 Hz.

Subsonic vs Infrasonic: Which One Is The Correct One?

Are you familiar with the terms subsonic and infrasonic? Do you know the difference between the two? In this article, we will explore the meanings of these

thecontentauthority.com

... and no subsonic isn't only used to refer to a speed (i.e. slower than then speed of sound), as above it can be and is attributed to sound wave frequency.


JSmith

 

[Hipster Doofus]

if you have 2 helpings pancakes make a great second order Butterworth filter

 

[Michael Fidler]

if you have 2 helpings pancakes make a great second order Butterworth filter

If you add a third pancake on top and knock them slightly askew, you'll have a super Chebyshev filter (0.01dB ripple works well). Easy to get 0.03dB at 40Hz, -3dB at 24Hz, and -22dB at 10Hz!

 

[Listener#1]

Rumble filters are very intentional in this model. They are used for 78's. The cut is for those frequencies that aren't even 'there' in the recording with 78's. Amir missed it this time and it's fairly-common knowledge. It's on many older preamps of the distant past. The interwebs have info.

The unit measures very well for a phono stage and being from another country outside of China, at an expected price point. LA is a small company and higher priced labor for the work performed. LA also has decades of brand identity, contributing to the price. It adds a rumble filter, which to older listeners adds functionality for 78's. It also sounds substantially better than a Project Phono Box. I've heard both.

 

[Andreas007]

Overpriced with technical flaws and no stand alone features. Rated poor.
Come on, these companies think it is still the 90‘s where you could get 500 % margin out of simple electronics in pretty cases.
Thanks to Amir who changed this game!

 

[amirm]

Rumble filters are very intentional in this model. They are used for 78's. The cut is for those frequencies that aren't even 'there' in the recording with 78's. Amir missed it this time and it's fairly-common knowledge. It's on many older preamps of the distant past. The interwebs have info.

The crapshoot that is 78 LP equalization, doesn't lend itself to optimal playback on this pre-amp. You would need a much more programmable phono stage which would then include both low and high cut filters.

 

[Michael Fidler]

Rumble filters are very intentional in this model. They are used for 78's. The cut is for those frequencies that aren't even 'there' in the recording with 78's. Amir missed it this time and it's fairly-common knowledge. It's on many older preamps of the distant past. The interwebs have info.

The unit measures very well for a phono stage and being from another country outside of China, at an expected price point. LA is a small company and higher priced labor for the work performed. LA also has decades of brand identity, contributing to the price. It adds a rumble filter, which to older listeners adds functionality for 78's. It also sounds substantially better than a Project Phono Box. I've heard both.

I highly doubt that, to be honest. For 78s, you would want a much higher-order filter, with a cutoff frequency slightly below 50Hz, as a lot of the LF disturbances are raised up through the spectrum by the higher relative velocity of the groove. This product would be horribly unsuitable for the 78s for the following reasons...

• A very high overload margin of well over 100mV is necessary due to the size of surface imperfections and their velocity (MM cartridges are velocity to voltage converters), especially at higher frequencies, and especially given that the kind of re-tipped DJ cartridges we are going to use for 78s if we are serious are approaching resonance as low as 17kHz. This phono preamp fails quite spectacularly in this regard at higher frequencies.
• Multiple playback curves are required, or at least a toggle switch to select British (300Hz/6400Hz) and American (RIAA 500Hz/2122Hz) characteristics to be able to play 90% of 78s with a reasonable degree of accuracy.
• A mono switch is also necessary to 78s, to cancel vertical noise picked up by stereo cartridges, which is very distracting indeed.
• Some sort of higher-order switchable low-pass filter will also be needed to stop out of band noise from distracting the listener above 7kHz or so, especially given cartridge resonances in the 15kHz to 20kHz region.

While it is true that some relatively costly parts have evidently been used, I don't feel that the price is justified considering the holistic performance. It seems apparent to me that these parts have been selected for their 'street cred' and the real job of engineering them together to give a decent result has been overlooked. We could build something substantially better than this using judiciously-placed SMD chip resistors, NJM4580s, and some C0G SMT capacitors for a parts cost of less than 2% of this product's retail price.

 

[laudio]

Guess I don't see the heavy duty construction aspect of this... look like a DIY project to me. In any case not worth the price.

 

[Mikig]

The discussion that arose around this test is interesting, and I learned something more! Thank you!
but I think that almost all buyers are not so sensitive to this type of technicality.

Lehmann sells? Yes!

because the products are good, they sound good, they maintain value over time, and, especially the basic models, perform well in their price range.
When you see the "blue resistors", and felt a greater mass in your hands, you already feel like you have a "high-end" product in your system. We also add that for most of the best-selling heads, they fit well.
And now the Lehmann name is a fixed point for phono preamps.

For the price? I open a separate chapter; objectively quite high, subjectively average: this scares me a little and depresses me a little, but the 2000 euros in the 2024 price range catalogue, for famous brands, have now become almost “normal”…..

 

[Endibol]

Rumble filters are very intentional in this model. They are used for 78's. The cut is for those frequencies that aren't even 'there' in the recording with 78's. Amir missed it this time and it's fairly-common knowledge. It's on many older preamps of the distant past. The interwebs have info.

The unit measures very well for a phono stage and being from another country outside of China, at an expected price point. LA is a small company and higher priced labor for the work performed. LA also has decades of brand identity, contributing to the price. It adds a rumble filter, which to older listeners adds functionality for 78's. It also sounds substantially better than a Project Phono Box. I've heard both.

Still very much more expensive than other European products that offer equal or even better performance.

 

[anmpr1]

Rumble filters are very intentional in this model. They are used for 78's. The cut is for those frequencies that aren't even 'there' in the recording with 78's.

There is nothing about 78 rpm at the company's Website, where they call it a 'soft bass roll-off filter'. However one of reprint reviews states that the designer used his particular circuit because he didn't want to add and extra active stage, preferring instead to keep it passive which, in his opinion, sounded better.

Three of the four reviews (really, subjective commentary) commented on the filter's obvious detrimental effect in the low bass. In addition (I'm not making this up) one reviewer claimed that the device didn't sound very good at all, at least until he replaced the mains cord with a much more expensive one than whatever came with the box.

 

[DrCWO]

For the price? I open a separate chapter; objectively quite high, subjectively average: this scares me a little and depresses me a little,

Reason for this is that it is sold by „classical“ dealers with a shop in the city. This increases the price by factor three. Ever seen such a dealer selling S.M.S.L? Sure not. S.M.S.L sells online and there is no chance for a „classical“ dealer to make any money. You can see lower prices most all brands selling online only.

 

[Mikig]

Reason for this is that it is sold by „classical“ dealers with a shop in the city. This increases the price by factor three. Ever seen such a dealer selling S.M.S.L? Sure not. S.M.S.L sells online and there is no chance for a „classical“ dealer to make any money. You can see lower prices most all brands selling online only.

I agree: if we then think that the shop often has skills, assistance and the possibility of demonstrating and lending components and warehouse, it is right that it is paid.

However, the upward trend in prices is now a fixed constant.
Often accompanied by release.2.3.4 etc... which makes everything that was on the list until the day before, age in one fell swoop, not always with macroscopic improvements....
Even Smsl that you mention is going and exceeding 1000 euros with many products .